Problem: What is the greatest common factor of $10$ and $16$ ? Another way to say this is: $\operatorname{gcf}(10, 16) = {?}$
The greatest common factor is the largest number that is a factor of both $10$ and $16$ The factors of $10$ are $1$ $2$ $5$ , and $10$ The factors of $16$ are $1$ $2$ $4$ $8$ , and $16$ Thus, the greatest common factor of $10$ and $16$ is $2$. $\operatorname{gcf}(10, 16) = 2$